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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull VDSO infrastructure updates from Thomas Gleixner:
- Consolidate the VDSO storage
The VDSO data storage and data layout has been largely architecture
specific for historical reasons. That increases the maintenance
effort and causes inconsistencies over and over.
There is no real technical reason for architecture specific layouts
and implementations. The architecture specific details can easily be
integrated into a generic layout, which also reduces the amount of
duplicated code for managing the mappings.
Convert all architectures over to a unified layout and common mapping
infrastructure. This splits the VDSO data layout into subsystem
specific blocks, timekeeping, random and architecture parts, which
provides a better structure and allows to improve and update the
functionalities without conflict and interaction.
- Rework the timekeeping data storage
The current implementation is designed for exposing system
timekeeping accessors, which was good enough at the time when it was
designed.
PTP and Time Sensitive Networking (TSN) change that as there are
requirements to expose independent PTP clocks, which are not related
to system timekeeping.
Replace the monolithic data storage by a structured layout, which
allows to add support for independent PTP clocks on top while reusing
both the data structures and the time accessor implementations.
* tag 'timers-vdso-2025-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
sparc/vdso: Always reject undefined references during linking
x86/vdso: Always reject undefined references during linking
vdso: Rework struct vdso_time_data and introduce struct vdso_clock
vdso: Move architecture related data before basetime data
powerpc/vdso: Prepare introduction of struct vdso_clock
arm64/vdso: Prepare introduction of struct vdso_clock
x86/vdso: Prepare introduction of struct vdso_clock
time/namespace: Prepare introduction of struct vdso_clock
vdso/namespace: Rename timens_setup_vdso_data() to reflect new vdso_clock struct
vdso/vsyscall: Prepare introduction of struct vdso_clock
vdso/gettimeofday: Prepare helper functions for introduction of struct vdso_clock
vdso/gettimeofday: Prepare do_coarse_timens() for introduction of struct vdso_clock
vdso/gettimeofday: Prepare do_coarse() for introduction of struct vdso_clock
vdso/gettimeofday: Prepare do_hres_timens() for introduction of struct vdso_clock
vdso/gettimeofday: Prepare do_hres() for introduction of struct vdso_clock
vdso/gettimeofday: Prepare introduction of struct vdso_clock
vdso/helpers: Prepare introduction of struct vdso_clock
vdso/datapage: Define vdso_clock to prepare for multiple PTP clocks
vdso: Make vdso_time_data cacheline aligned
arm64: Make asm/cache.h compatible with vDSO
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Commit 14be4e6f3522 ("selftests: vDSO: fix ELF hash table entry size for s390x")
changed the type of the ELF hash table entries to 64bit on s390x.
However the *GNU* hash tables entries are always 32bit.
The "bucket" pointer is shared between both hash algorithms.
On s390, this caused the GNU hash algorithm to access its 32-bit entries as if they
were 64-bit, triggering compiler warnings (assignment between "Elf64_Xword *" and
"Elf64_Word *") and runtime crashes.
Introduce a new dedicated "gnu_bucket" pointer which is used by the GNU hash.
Fixes: e0746bde6f82 ("selftests/vDSO: support DT_GNU_HASH")
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250217-selftests-vdso-s390-gnu-hash-v2-1-f6c2532ffe2a@linutronix.de
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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According to limits.h(2) ULONG_MAX is only guaranteed to expand to an
expression, not a symbolic constant which can be evaluated by the
preprocessor.
Specifically the definition of ULONG_MAX from nolibc can not be evaluated
by the preprocessor. To provide compatibility with nolibc, check with
__SIZEOF_LONG__ instead, with is provided directly by the preprocessor
and therefore always a symbolic constant.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/all/20250226-parse_vdso-nolibc-v2-13-28e14e031ed8@linutronix.de
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To allow the usage of parse_vdso.c together with a limited libc like
nolibc, use the kernels own elf.h and auxvec.h headers.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/all/20250226-parse_vdso-nolibc-v2-12-28e14e031ed8@linutronix.de
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There are no users left.
This also removes the usage of ElfXX_auxv_t, which is not formally
standardized.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/all/20250226-parse_vdso-nolibc-v2-11-28e14e031ed8@linutronix.de
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glibc added support for DT_GNU_HASH in 2006 and DT_HASH has been
obsoleted for more than one decade in many Linux distributions.
Many vDSOs support DT_GNU_HASH. This patch adds selftests support.
Link: https://lore.kernel.org/r/20241206130724.7944-2-xry111@xry111.site
Signed-off-by: Fangrui Song <i@maskray.me>
Tested-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Xi Ruoyao <xry111@xry111.site> # rebase
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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On powerpc64 as shown below by readelf, vDSO functions symbols have
type NOTYPE.
$ powerpc64-linux-gnu-readelf -a arch/powerpc/kernel/vdso/vdso64.so.dbg
ELF Header:
Magic: 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2's complement, big endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: DYN (Shared object file)
Machine: PowerPC64
Version: 0x1
...
Symbol table '.dynsym' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
...
1: 0000000000000524 84 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
...
4: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LINUX_2.6.15
5: 00000000000006c0 48 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
Symbol table '.symtab' contains 56 entries:
Num: Value Size Type Bind Vis Ndx Name
...
45: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LINUX_2.6.15
46: 00000000000006c0 48 NOTYPE GLOBAL DEFAULT 8 __kernel_getcpu
47: 0000000000000524 84 NOTYPE GLOBAL DEFAULT 8 __kernel_clock_getres
To overcome that, commit ba83b3239e65 ("selftests: vDSO: fix vDSO
symbols lookup for powerpc64") was applied to have selftests also
look for NOTYPE symbols, but the correct fix should be to flag VDSO
entry points as functions.
The original commit that brought VDSO support into powerpc/64 has the
following explanation:
Note that the symbols exposed by the vDSO aren't "normal" function symbols, apps
can't be expected to link against them directly, the vDSO's are both seen
as if they were linked at 0 and the symbols just contain offsets to the
various functions. This is done on purpose to avoid a relocation step
(ppc64 functions normally have descriptors with abs addresses in them).
When glibc uses those functions, it's expected to use it's own trampolines
that know how to reach them.
The descriptors it's talking about are the OPD function descriptors
used on ABI v1 (big endian). But it would be more correct for a text
symbol to have type function, even if there's no function descriptor
for it.
glibc has a special case already for handling the VDSO symbols which
creates a fake opd pointing at the kernel symbol. So changing the VDSO
symbol type to function shouldn't affect that.
For ABI v2, there is no function descriptors and VDSO functions can
safely have function type.
So lets flag VDSO entry points as functions and revert the
selftest change.
Link: https://github.com/mpe/linux-fullhistory/commit/5f2dd691b62da9d9cc54b938f8b29c22c93cb805
Fixes: ba83b3239e65 ("selftests: vDSO: fix vDSO symbols lookup for powerpc64")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-By: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/b6ad2f1ee9887af3ca5ecade2a56f4acda517a85.1728512263.git.christophe.leroy@csgroup.eu
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The vDSO self tests fail on s390x for a vDSO linked with the GNU linker
ld as follows:
# ./vdso_test_gettimeofday
Floating point exception (core dumped)
On s390x the ELF hash table entries are 64 bits instead of 32 bits in
size (see Glibc sysdeps/unix/sysv/linux/s390/bits/elfclass.h).
Fixes: 40723419f407 ("kselftest: Enable vDSO test on non x86 platforms")
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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On powerpc64, following tests fail locating vDSO functions:
~ # ./vdso_test_abi
TAP version 13
1..16
# [vDSO kselftest] VDSO_VERSION: LINUX_2.6.15
# Couldn't find __kernel_gettimeofday
ok 1 # SKIP __kernel_gettimeofday
# clock_id: CLOCK_REALTIME
# Couldn't find __kernel_clock_gettime
ok 2 # SKIP __kernel_clock_gettime CLOCK_REALTIME
# Couldn't find __kernel_clock_getres
ok 3 # SKIP __kernel_clock_getres CLOCK_REALTIME
...
# Couldn't find __kernel_time
ok 16 # SKIP __kernel_time
# Totals: pass:0 fail:0 xfail:0 xpass:0 skip:16 error:0
~ # ./vdso_test_getrandom
__kernel_getrandom is missing!
~ # ./vdso_test_gettimeofday
Could not find __kernel_gettimeofday
~ # ./vdso_test_getcpu
Could not find __kernel_getcpu
On powerpc64, as shown below by readelf, vDSO functions symbols have
type NOTYPE, so also accept that type when looking for symbols.
$ powerpc64-linux-gnu-readelf -a arch/powerpc/kernel/vdso/vdso64.so.dbg
ELF Header:
Magic: 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2's complement, big endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: DYN (Shared object file)
Machine: PowerPC64
Version: 0x1
...
Symbol table '.dynsym' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000524 84 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
2: 00000000000005f0 36 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
3: 0000000000000578 68 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
4: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LINUX_2.6.15
5: 00000000000006c0 48 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
6: 0000000000000614 172 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
7: 00000000000006f0 84 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
8: 000000000000047c 84 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
9: 0000000000000454 12 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
10: 00000000000004d0 84 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
11: 00000000000005bc 52 NOTYPE GLOBAL DEFAULT 8 __[...]@@LINUX_2.6.15
Symbol table '.symtab' contains 56 entries:
Num: Value Size Type Bind Vis Ndx Name
...
45: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LINUX_2.6.15
46: 00000000000006c0 48 NOTYPE GLOBAL DEFAULT 8 __kernel_getcpu
47: 0000000000000524 84 NOTYPE GLOBAL DEFAULT 8 __kernel_clock_getres
48: 00000000000005f0 36 NOTYPE GLOBAL DEFAULT 8 __kernel_get_tbfreq
49: 000000000000047c 84 NOTYPE GLOBAL DEFAULT 8 __kernel_gettimeofday
50: 0000000000000614 172 NOTYPE GLOBAL DEFAULT 8 __kernel_sync_dicache
51: 00000000000006f0 84 NOTYPE GLOBAL DEFAULT 8 __kernel_getrandom
52: 0000000000000454 12 NOTYPE GLOBAL DEFAULT 8 __kernel_sigtram[...]
53: 0000000000000578 68 NOTYPE GLOBAL DEFAULT 8 __kernel_time
54: 00000000000004d0 84 NOTYPE GLOBAL DEFAULT 8 __kernel_clock_g[...]
55: 00000000000005bc 52 NOTYPE GLOBAL DEFAULT 8 __kernel_get_sys[...]
Fixes: 98eedc3a9dbf ("Document the vDSO and add a reference parser")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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When building with clang, via:
make LLVM=1 -C tools/testing/selftests
...there are several warnings, and an error. This fixes all of those and
allows these tests to run and pass.
1. Fix linker error (undefined reference to memcpy) by providing a local
version of memcpy.
2. clang complains about using this form:
if (g = h & 0xf0000000)
...so factor out the assignment into a separate step.
3. The code is passing a signed const char* to elf_hash(), which expects
a const unsigned char *. There are several callers, so fix this at
the source by allowing the function to accept a signed argument, and
then converting to unsigned operations, once inside the function.
4. clang doesn't have __attribute__((externally_visible)) and generates
a warning to that effect. Fortunately, gcc 12 and gcc 13 do not seem
to require that attribute in order to build, run and pass tests here,
so remove it.
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Edward Liaw <edliaw@google.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Both vdso_test_gettimeofday and vdso_standalone_test_x86 use the library in
parse_vdso.c but each separately declares the API it offers which is not
ideal. Create a header file with prototypes of the functions and use it in
both the library and the tests to ensure that the same prototypes are used
throughout.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Remove vDSO from Makefile to move the to selftests. Update vDSO Makefile
to work under selftests. vDSO will not be run as part of selftests suite
and will not be included in install targets. They can be built separately
for now.
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
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